A number of homogeneous and heterogeneous acidic catalysts useful for the Friedel-Crafts reactions, for examples alkylation, polyalkylation, aralkylation, acylation, aroylation and the like, are known in the prior art. Aralkylated aromatic compounds are useful fine chemicals and these are also used as intermediates in a member of organic syntheses. Both the homogeneous and heterogeneous catalysed liquid phase processes for the preparation of aralkylated aromatic compounds are known in the prior art,
Homogeneous Catalysts for Friedel-Crafts Reactions
The acylation and benzoylation of aromatic compounds and related Friedel-Crafts type reaction using homogeneous lewis acid catalysts are well-known in the prior art [ref G. A. Olah, in Friedel-Crafts and related reactions: vol. III, Acylation and related reactions, Wiley-Interscience Publ., New York, 1964].
A use of CuCl.sub.2 as a homogeneous catalyst in the benzylation of benzene or substituted benzenes by benzyl chloride is disclosed in two U.S. patents, U.S. Pat. No. 3,678,122 (1972) and U.S. Pat. No. 3,679,760 (1972), A French patent, Fr. Demande 2,144,578 (1973), disclosed benzylation of p-substituted phenols by benzyl halides in the presence of homogeneous ZnCl.sub.2 catalyst. A USSR patent, U.S.S.R. 394,353 (1973), disclosed a use Of SnSO.sub.4 or SnCl.sub.2 as homogeneous catalyst for the benzylation with benzyl chloride of m-dimethoxy benzene, A Japanese patent, Japan Kokai 7399,154 (1973), disclosed preparation of dibenzyl benzene derivatives by benzylation of benzene or substituted benzenes using AlCl.sub.3, FeCl.sub.3 and 98% H.sub.2 SO.sub.4. A use of H.sub.2 SO.sub.4 or H.sub.3 PO.sub.4 and optionally 4-CH.sub.3 C.sub.6 H.sub.4 SO.sub.3 H, ZnCl.sub.2, BF.sub.3, etc. in the preparation of o-benzyltoluenes by the reaction of .alpha. o-chloromethyltoluene with a benzene derivative is disclosed in a German patent, Ger. Offen 2,456,747 (1976). A use of phosphoric acid and optionally H.sub.2 SO.sub.4 or a Friedel-Crafts type metal halide in the benzylation of benzene with benzylether is disclosed in a U.S. patent, U.S. Pat. No. 4,049,733 (1977).
A German patent, Ger.offen 2,451,037 (1976), disclosed the use of HF as a catalyst for the benzoylation of aromatic compounds.
A French patent, Fr. Demande FR 2,496,097 (1982) disclosed the acylation of benzene by phthaleic anhydride using HF--BF.sub.3 mixture.
More recently, an European Patent, Eur.Pat.Appl.FP 538,704 (1993), disclosed a process for the preparation of p-substituted o-benzylphenols by treating phenols, p-R'C.sub.6 H.sub.4 OH (R'=halo, alkyl, OH, alkoxy, alkylmercapto, aryl, aryloxy or arylmercapto), with ArCH.sub.2 X (Ar=corresponding aryl nucleus; X=halo, arylcarboxy, phenylsulfatoxy, hydroxy, alkoxy etc.) in a continuously functioning distillation apparatus in the presence of dissolved acid catalyst.
The main disadvantages of the use of homogeneous acid catalyst for the Friedel-Crafts processes are as follows:
1) The separation and recovery of the dissolved acid catalysts from the liquid reaction mixture is difficult. PA0 2) The disposal of the used acid catalysts creates environmental pollution. PA0 3) The homogeneous acid catalysts also pose several other problems such as high toxicity, corrosion, spent acid disposal and use of more than the stoichiometric amount. PA0 (i) The separation and recovery of the dissolved acid catalysts from the liquid reaction mixture is difficult. PA0 (ii) The disposal of the used acid catalysts creates environmental pollution. PA0 (iii) The homogeneous acid catalysts also pose several other problems such as high toxicity, corrosion, spent acid disposal and use of more than the stoichiometric amount. PA0 (i) depositing on said catalyst support mixed metal halides represented by formula: EQU A.sub.a MD.sub.d, PA0 wherein A is selected from chemical elements Ga, Al, B, Zn, Fe, Sn, Ti, Th, Zr or a mixture of two or more thereof; M is selected from chemical elements In, Tl or a mixture thereof; D is chemical group selected from halogen Cl, Br or I or a mixture thereof; a is A/M mole ratio in the range of about 0.001 to about 100; and d is number of atoms of D needed to fulfil the valence requirement of the metallic elements A/M; from non-aqueous moisture-free solvent, in which said mixed metal halides are dissolved, by known catalyst impregnating techniques, such that the weight percent loading of said mixed metal halides on said catalyst support is in the range of about 0.5 wt % to about 50 wt %; or depositing on said catalyst support mixed metal compounds represented by formula: EQU A.sub.a ME.sub.e, PA0 wherein A is selected from chemical elements Ga, Al, B, Zn, Fe, Sn, Ti, Th, Zr or a mixture of two or more thereof; M is selected from chemical elements In, Tl or a mixture thereof; E is chemical group selected from O, NO.sub.3, OH, halo, alkoxides or C.sub.n H.sub.2n+1 COO, wherein n is in the range of 0 to 15; a is A/M mole ratio in the range of about 0,001 to about 100; e is number of groups of E needed to fulfil the valence requirement of the metallic elements A.sub.a M; by known catalyst impregnation, coating or co-precipitation techniques, such that the weight percent loading of said catalyst support is in the range of about 0.5 wt % to about 50 wt %, PA0 (ii) heating the catalyst mass obtained from the step-i to dryness at a temperature of about 25.degree. C. to about 250.degree. C. under vacuum or in presence of air or inert gas, calcining the dried mass obtained from step-ii at a temperature of about 100.degree. C. to about 700.degree. C. under vacuum or in presence of air or inert gas for about 0.1 h to about 100 h, and also provides a catalytic process for the preparation of aralkylated aromatic compounds represented by a general chemical formula: EQU R.sub.1 R.sub.2 R.sub.3 R.sub.4 C.sub.n H.sub.2n C.sub.6 H.sub.3 R.sub.5 R.sub.6, PA0 by a liquid phase aralkylation of aromatic compounds, called substrates, represented by a general chemical formula: EQU R.sub.1 R.sub.2 R.sub.3 R.sub.4 M, PA0 wherein is C.sub.6 H.sub.1 or C.sub.10 H.sub.3 or C.sub.14 H.sub.5 ; M is C.sub.6 H.sub.2 or C.sub.10 H.sub.4 or C.sub.14 H.sub.6 ; each of R.sub.1, R.sub.2, R.sub.3 and R.sub.4 groups is H or C.sub.n H.sub.2n+1 or C.sub.p H.sub.2p-1 or C.sub.6 H.sub.5 or C.sub.n H.sub.2n C.sub.6 H.sub.5 or OH or OC.sub.n H.sub.2n+1 or OC.sub.6 H.sub.5 or halogen or C.sub.n H.sub.2n+1-x Y.sub.x or NO.sub.2 or NH.sub.2 or NHC.sub.n H.sub.2n+1 or N(C.sub.n H.sub.2n+1).sub.2 or NHCOC.sub.n H.sub.2n+1 or NHCOC.sub.6 H.sub.5 or CN or CHO or COOH or COOC.sub.n H.sub.2n+1 or COC.sub.n H.sub.2n+1 or SO.sub.3 H or SO.sub.3 C.sub.n H.sub.2n+1 or SH or alkyl mercapto group or aryl mercapto group; each of R.sub.5 and R.sub.6 group is H or CH.sub.3 or C.sub.2 H.sub.5 or OH or OCH.sub.3 or OC.sub.2 H.sub.5 or NO.sub.2 or halogen or NH.sub.2 ; X is halogen or OH or SO.sub.3 H or COOH or OC.sub.n H.sub.2n C.sub.6 H.sub.5 or OC.sub.n H.sub.2n+1 or aryl carboxy group or alkyl carboxy group, x is an integer between 1 and 2n+1 and n & p are integers greater than or equal to 1 and 2, respectively, and C, H, N, O and S are chemical elements, using the above supported solid catalyst; the process comprises PA0 (i) depositing on said catalyst support mixed metal halides represented by formula: EQU A.sub.a MD.sub.d, PA0 wherein A is selected from chemical elements Ga, Al, B, Zn, Fe, Sn, Ti, Th, Zr or a mixture of two or more thereof, M is selected from chemical elements In, Tl or a mixture thereof; D is chemical group selected from halogen Cl, Br or I or a mixture thereof, a is A/M mole ratio in the range of about 0.001 to about 100; and d is number of atoms of D needed to fulfil the valence requirement of the metallic elements A.sub.a M; from non-aqueous moisture-free solvent, in which said mixed metal halides are dissolved, by known catalyst impregnating techniques, such that the weight percent loading of said mixed metal halides on said catalyst support is in the range of about 0.5 wt % to about 50 wt %; or depositing on said catalyst support mixed metal compounds represented by formula: EQU A.sub.a ME.sub.e, PA0 wherein A is selected from chemical elements Ga, Al, B, Zn, Fe, Sn, Ti, Th, Zr or a mixture of two or more thereof, M is selected from chemical elements In, Tl or a mixture thereof; E is chemical group selected from O, NO.sub.3, OH, halo, alkoxides or C.sub.n H.sub.2n+1 COO, wherein n is in the range of 0 to 15; a is A/M mole ratio in the range of about 0,001 to about 100; e is number of groups of E needed to fulfil the valence requirement of the metallic elements A.sub.a M; by known catalyst impregnation, coating or co-precipitation techniques, such that the weight percent loading of said catalyst support is in the range of about 0.5 wt % to about 50 wt %, PA0 (ii) heating the catalyst mass obtained from the step-i to dryness at a temperature of about 25.degree. C. to about 250.degree. C. under vacuum or in presence of air or inert gas, calcining the dried mass obtained from step-ii at a temperature of about, 100.degree. C. to about 700.degree. C. under vacuum or in presence of air or inert gas for about 0.1 h to about 100 h; PA0 ii) contacting a liquid mixture of aromatic compound and aralkylating agent having a mole ratio of aromatic compound to aralkylating agent between 0.1 and 100, in the absence or presence of a solvent, with said pretreated supported solid catalyst at a weight ratio of said catalyst to aralkylating agent between 0.02 and 2,0 in a stirred batch reactor in the presence of an inert gas bubbling through the reaction mixture and allowing the reaction to occur at a temperature between 25.degree. C. and 300.degree. C. at a pressure between 1 atm and 10 atm for a reaction period between 0.01 h and 50 h, PA0 iii) cooling the reaction mixture to a temperature about 25.degree. C., removing said catalyst from the reaction mixture by filtration and then separating the reaction products from the reaction mixture by the known methods.
Heterogeneous Catalysts for Friedel-Crafts Reactions
A German patent, Ger.Offen 2,547,030 (1977), disclosed the preparation of o-benzyltoluenes by the reaction of o-methylbenzyl halides with substituted benzenes in the presence of Al-silicate. The 2-CH.sub.3 C.sub.6 H.sub.4 CH.sub.2 Cl was stirred with toltuene and Al-silicate (25%Al.sub.2 O.sub.3) at 110.degree. C. to give 81% 2-methylbenzyltoluene. According to a Japanese patent, Jpn. Kokai Tokkyo Koho JP 59,186,937 (1984), o-benzylphenol was prepared by the liquid phase reaction of benzyl alcohol with phenol in the presence of .gamma.-Al.sub.2 O.sub.3. For example 7.5 g .gamma.-Al.sub.2 O.sub.3 was added to a mixture of 32.5 g benzyl alcohol and 47 g phenol at 190.degree. C. under stirring to give a product containing 49.9% o-benzylphenol. A German Patent, Ger. Offen DE 3,700,917 (1988), disclosed the preparation of p-substituted o-benzylphenols by benzylation of p-substituted phenols with benzylalcohol in the presence of Na--Y type zeolite. A mixture of 0.5 mole 4-ClC.sub.6 H.sub.4 OH, 0 1 mole C.sub.6 H.sub.5 CH.sub.2 OH and 0,6 g of Na-Y type zeolite was heated at 200.degree. C. for 3 hrs to give 25.4% 2-benzyl-4-chlorophenol.
A French patent, Fr. Demande FR 2,667,063 (1992), disclosed the preparation of 4-substituted benzophenones by aroylation of substituted benzenes by substituted benzoic acid in the presence of HY and H.beta. type zeolites. Accordingly 4-ClC.sub.6 H.sub.4 COOH and PhMe were heated 4 h at 200.degree. C. under 2.times.10.sup.5 Pa in the presence of calcined zeolite H.beta. to give 84.4% 4-(4-ClC.sub.6 H.sub.4 CO) C.sub.6 H.sub.4 Me.
A recent paper by Vincent et al. (ref Tetrahedron Lett. 35, 1994, 2601), disclosed that H-ZSM-5 zeolite can catalyze the benzoylation by benzoyl chloride of phenol and anisole but not the benzoylation with benzoyl chloride of benzene, halobenzene and naphthalene, at 120.degree. C. for 5 h.
A German patent, Ger. Offen DE 3,436,780 (1990), disclosed the process for the preparation of benzylbenzenes from benzenes and benzyl alcohols in the presence of activated bleaching earth and a diluent at 90-140.degree. C. According to Japanese patent, Jpn Kokai Tokkyo Koho JP 03,170,442 (1991), benzylbiphenyls are manufactured by benzylating biphenyl and diphenylmethane with .gtoreq.1 compound from benzyl halides, benzyl alcohol, benzyl ether in the presence of a zeolite or silica-alumina catalyst. An European patent, Eur.Pat. appl. EP 428,081 (1991), disclosed a process of benylation of alkylbenzenes with benzyl chloride in the presence of H--Y or H--L zeolite catalyst. According to a German patent, Ger. Offen DE 4,038,933 (1992), disclosed a process for benzylation of aromatics using technical carbon catalysts.
Alkylation, aralkylation, acylation or aroylation of aromatic compound involves electrophilic substitution of H from the aromatic nucleus of the aromatic compound. It is well known in the prior art that the electrophilic substitution is favoured by the presence of electron donating groups, such as OH, alkyl, alkoxy, phenoxy, amine, alkyl amine, SH etc., in the aromatic compound. Whereas the electrophilic substitution is inhibited by the presence of electron withdrawing groups such as halo, nitro, cyano, carboxy, aldehyde, etc, in the aromatic compound, [ref, G. A. Olah, in Friedel-Crafts and related reactions, Wiley-Interscience Publ., New York, 1963].
Although some limitations of the homogeneous acid catalyzed processes are overcome in the prior art heterogeneous catalyzed processes described above, the alkylating, aralkylating, acylating or aroylating activity of the solid catalysts used in the prior art processes are low, particularly for alkylating, aralkylating, acylating or aroylating aromatic compounds containing electron withdrawing groups. Hence there is a great practical need for finding more efficient solid catalyst for the alkylating, aralkylating, acylating or aroylating of aromatic compounds. There is also a need for finding highly efficient solid catalyst also for the alkylating, aralkylating, acylating or aroylating of aromatic compounds containing electron withdrawing groups such as halo, nitro, cyano, carboxy, aldehyde, etc.,
Homogeneous Acid Catalysed Processes for Aralkylated Aromatic Compounds
According to a U.S. patent, U.S. Pat. No. 3,678,122 (1972), diphenylmethane was prepared by treating a mixture of benzene and benzyl chloride with CuCl.sub.2. A U.S. patent, U.S. Pat. No. 3,679,760 (1972), disclosed the preparation of diaryl alkanes by refluxing benzyl chloride, C.sub.6 H.sub.4 R.sub.1 R.sub.2 (where R.sub.1 =H and R.sub.2 =H, CH.sub.3 or OH) and CuCl.sub.2.
A French patent, Fr. Demande 2,144,578 (1973), disclosed that substituted phenols p-RC.sub.6 H.sub.4 OH (where R=halogen or C.sub.1-4 -alkyl) are benzylated by benzyl halides in the presence of ZnCl.sub.2. A USSR patent, U.S.S.R. 394,353 (1973), disclosed preparation of 2,6- and 2,4-(CH.sub.3 O).sub.2 C.sub.6 H.sub.3 CH.sub.2 C.sub.6 H.sub.5 by treating m-(CH.sub.3 O).sub.2 C.sub.6 H.sub.4 with benzyl chloride in the presence of SnSO.sub.4 catalyst at 145-150.degree. C., or SnCl.sub.2 catalyst at 165-170.degree. C. A Japanese patent, Japan Kokai 7399,154 (1973), disclosed preparation of dibenzyl benzene derivatives by benzylation of benzene or substituted benzenes using Friedel-Crafts catalyst e.g., AlCl.sub.3, FeCl.sub.3 and 98% H.sub.2 SO.sub.4. According to this patent, 200 g .alpha.-methyl benzyl chloride was added to a refluxing mixture of 500 g benzene and 5 g AlCl.sub.3 and the whole mixture refluxed for 5 h to give 120 g .alpha.-methyl bezylbenzene.
According to a German patent, Ger. Offen 2,456,747 (1976), o-benzyltoluenes were prepared in .about.90% yields by the reaction of .alpha. o-chloromethyltoluene with a benzene derivative in .gtoreq.1:7 ratio in the presence of H.sub.2 SO.sub.4 and/or H.sub.3 PO.sub.4 and optionally 4-CH.sub.3 C.sub.6 H.sub.4 SO.sub.3 H, ZnCl.sub.2, BF.sub.3, etc. Thus 135 parts 85% H.sub.3 PO.sub.4, 270 parts 85% H.sub.2 SO.sub.4, 10 parts 4-CH.sub.3 C.sub.6 H.sub.4 SO.sub.3 H, 70 parts 2CH.sub.3 C.sub.6 H.sub.4 CH.sub.2 Cl and 390 parts of C.sub.6 H.sub.6 were heated at 75-80.degree. C. for 4 h to give 89% 2-CH.sub.3 C.sub.6 H.sub.4 CH.sub.2 C.sub.6 H.sub.5.
An U.S. patent U.S. Pat. No. 4,049,733 (1977), disclosed preparation of diphenylmethane by benzylation of benzene with benzylether using phosphoric acid and optionally H.sub.2 SO.sub.4 or a Friedel-Crafts type metal halide.
European patent, Eup.Pat.Appl.EP 37,628 (1981), disclosed preparation of diphenylmethane by benzylation of benzene with chloromethylbenzenes in the presence of H.sub.2 SO.sub.4 and a cationic surfactant or a non-ionic surfactant which is susceptible to protonation under strong acidic conditions.
A German patent, Ger.Offen DF 3,922,518 (1991), disclosed a process for the manufacture of .alpha.-methylbenzylphenol derivatives, which comprises the treatment of C.sub.1-4 -alkyl substituted phenols with styrene in the presence of phosphorus chloride catalyst. More recently, an European Patent, Eur.Pat.Appl.FP 538,704 (1993), disclosed a process for the preparation of p-substituted o-benzylphenols by treating phenols, p-R'C.sub.6 H.sub.4 OH (R'=halo, alkyl, OH, alkoxy, alkylmercapto, aryl, aryloxy or arylmercapto), with ArCH.sub.2 X (Ar=corresponding aryl nucleus; X=halo, arylcarboxy, phenylsulfatoxy, hydroxy, alkoxy etc.) in a continuously functioning distillation apparatus in the presence of dissolved acid catalyst.
The main disadvantages of the homogeneous acid catalyzed processes are as follows:
Heterogeneous acid catalyzed processes for Aralkylated Aromatiuc Compounds
A German patent, Ger.Offen 2,547,0310 (1977), disclosed the preparation of o-benzyl-toluenes by the reaction of o-methylbenzyl halides with substituted benzenes in the presence of Al-silicate. The 2-CH.sub.3 C.sub.6 H.sub.4 CH.sub.2 Cl was stirred with toluene and Al-silicate (25% Al.sub.2 O.sub.3) at 110.degree. C. to give 81% 2-methylbenzyltoluene. According to a Japanese patent, Jpn. Kokai Tokkyo Koho JP 59,186,937 (1984), o-benzylphenol was prepared by the liquid phase reaction of benzyl alcohol with phenol in the presence of .gamma.-Al.sub.2 O.sub.3. For example 7.5 g .gamma.-Al.sub.2 O.sub.3 was added to a mixture of 32.5 g benzyl alcohol and 47 g phenol at 190.degree. C. under stirring to give a product containing 49.9% o-benzylphenol. A German patent, Ger. Offen DE 3,700,917 (1988), disclosed the preparation of p-substituted o-benzylphenols by benzylation of p-substituted phenols with benzylalcohol in the presence of Na--Y type zeolite. A mixture of 0.5 mole 4-ClC.sub.6 H.sub.4 OH, 0.1 mole C.sub.6 H.sub.5 CH.sub.2 OH and 0.6 g of Na--Y type zeolite was heated at 200.degree. C. for 3 hrs to give 25.4% 2-benzyl-4-chlorophenol.
A German patent, Ger. Offen DE 3,836,780 (1990), disclosed the process for the preparation of benzylbenzenes from benzenes and benzyl alcohols in the presence of activated bleaching earth and a diluent at 90-140.degree. C. According to Japanese patent, Jpn Kokai Tokkyo Koho JP 03,170,442 (1991), benzylbiphenyls are manufactured by benzylating biphenyl and diphenylmethane with .gtoreq.1 compound from benzyl halides, benzyl alcohol, benzyl ether in the presence of a zeolite or silica-alumina catalyst. An European patent, Eur.Pat. appl. FP 428,081 (1991), disclosed a process of benzylation of alkylbenzenes with benzyl chloride in the presence of H--Y or H--L zeolite catalyst. According to a German patent, Ger. Offen DE 4,038,933 (1992), disclosed a process for benzylation of aromatics using technical carbon catalysts.
Aralkylation of aromatic compounds by aralkylating agent involves electrophilic substitution of H from the aromatic nucleus. It is well known in the prior art that the electrophilic substitution is favoured by the presence of electron donating groups, such as OH, alkyl, alkoxy, phenoxy, amine, alkyl amine, SH etc., in the aromatic compound to be aralkylated. Whereas in the absence of the electron donating groups, e.g. for benzene, naphthalene and anthracene, the aralkylation is relatively difficult [ref G. A. Olah, in Friedel-Crafts and related reactions, Wiley-Interscience Publ., New York, 1963].
Although some limitations of the homogeneous acid catalyzed processes are overcome by the prior art heterogeneous catalyzed processes described above, the aralkylating activity of the solid catalysts used in the above processes are low, particularly for aralkylating aromatic compounds not containing electron donating groups. Hence there is a great practical need for developing a process for the aralkylation of aromatic compounds with aralkylating agent, using more efficient, easily separable and reusable solid catalyst, There is also a need for developing a catalytic process for the aralkylation of aromatic compounds not containing electron donating groups, using highly efficient, easily separable and reusable solid catalyst.
This invention is made with the following objectives so that most of the drawbacks or limitations of the prior art homogeneous and heterogeneous catalyzed processes for the aralkylation of aromatic compounds could be overcome.
Accordingly, the main object of the present invention is to provide a novel supported catalyst comprising mixed metal oxides or halides, which has high activity for the Friedel-Crafts reactions not only when the aromatic ring activating groups (i.e. electron donating groups such as alkyl, hydroxy alkoxy, etc) are present in the aromatic ring to be aralkylated, acylated or aroylated but also when the ring activating group is absent or when aromatic ring deactivating groups (i.e. electron withdrawing groups such as halo, nitro, etc) are present in the aromatic ring to be aralkylated, acylated or aroylated, so that the reaction temperature is low and/or time for completing the reaction is short.and which can be used repeatedly for the catalytic rections, and also to provide an improved catalytic process for the preparation of aralkylated aromatic compound by the aralkylation of aromatic compound, with or without containing electron donating group, using the supported catalyst which is highly active supported solid catalyst comprising mixed metal oxides or halides deposited on micro-, meso- or macroporous catalyst carrier or support and has a high activity not only when the aromatic ring activating groups (i.e. electron donating groups such as alkyl, alkoxy, hydroxy, phenoxy, etc.) are present in the aromatic ring to be aralkylated but also when the ring activating group in the aromatic ring to be aralkylated is absent, so that the reaction temperature is low and/or time for completing the reaction is short.
Other important object of this invention is to provide a liquid phase process for the aralkylation of aromatic compounds using the novel supported solid catalyst which is easily separable and reusable in the process for several times.
Another important object of this invention is to provide a solid catalyzed liquid phase process for the aralkylating aromatic compounds even in the presence of moisture in the reaction mixture.